I have had a P800 stating I am due a tax refund. It further states the cheque has been sent to "Claim My Tax Limited". I have no knowledge of this company and don't recall signing a Deed of Assignment. When I contact them they have promised to transfer the money but it has never arrived - I have been waiting 4 weeks. How can i find out if they are legimate and how they have been approved to receive this cheque?